In the field of prosthetics, an amputee can attach a prosthetic limb to the residual limb via a socket of the prosthesis using a variety of mechanical attachment or suspension mechanisms. A suspension system usually relies on creating a vacuum or negative air pressure in the space between the socket and the surface of the residual limb. A seal is created by covering the brims of the socket with a sleeve. The seal for the vacuum space, however, is not airtight, so air may leak into the vacuum space weakening the attachment.
As a result, there is a need for a system which can create and maintain negative air pressure during use.
In some prosthetic systems, when weight is applied to a prosthetic attachment such as a prosthetic foot, the applied weight causes the vacuum pump to decrease the volume of the pump and expel air out of the pump. Then, when the compressive force is removed, the pump expands and draws air out of the vacuum space to create a vacuum effect. In these types of systems, the system relies on a complete compression of the pump in expelling air in each cycle to use the pump to its maximum capacity. It is difficult for complete compression to occur in every cycle using the gait of a user as the compressive force since the impact and displacement of the pump may not be consistent and can vary between users.